Hector Ambriz sent down, Chia-Jen Lo and Josh Zeid called up

The Astros have optioned RHP Hector Ambriz to Triple-A Oklahoma City and recalled RHP Chia-Jen Lo from Double-A Corpus Christi and RHP Josh Zeid from Triple-A Oklahoma City, the team announced.

Lo and Zeid will be making their debuts on an active MLB roster.

Lo, 27, owns a 3.24 ERA with six saves in 17 appearances combined between Corpus Christi, Single-A Quad Cities and Single-A Tri-City this season. He has 20 strikeouts in 16.2 innings, while allowing a .234 opponent’s batting average. He joined Corpus Christi on July 10. Lo was one of the final cuts this spring where he had a 2.08 ERA in nine appearances for the Astros.

Zeid, 26, has gone 4-1 with 13 saves and a 3.50 ERA in 43 relief appearances for Oklahoma City this season. He has served as the RedHawks closer since June 15 and is 13-for-15 in save opportunities in 2013. Zeid has posted 53 strikeouts in his 43.2 innings pitched, while allowing a .231 opponent’s batting average. Zeid also pitched well in spring training, making six appearances and posting a 1.50 ERA.

Ambriz, 29, has made 43 relief appearances for the Astros this season over two stints with the club. He most recently returned to Houston on July 19.

The moves fill out the Astros bullpen after the team traded closer Jose Veras to Detroit earlier in the day for a minor-league outfielder and a player to be named later.